A skill is a versioned instruction module that Claude Code loads at runtime — coding standards, review protocols, accessibility checklists written down once and applied the same way on every project. Zivtech maintains a library of 80+ skills; the installed working set as of June 2026 is 101 modules.
The library breaks down to 36 reviewers (critics), 33 planners, 13 executors, 4 writers and builders, and 15 other specialists. The ratio is the point: reviewers outnumber executors almost three to one, because review is the governing layer of AI-assisted delivery, not an afterthought.
The skill library itself is private today. The platform core that loads and governs skills is public, so the mechanism is inspectable even where the library is not.